Slim

Request

Retrieving Data

Form Data

Use the context method Context#FormValue(name string) to get form data by field name:

Get form data
// Handlerfunc(c slim.Context) error {    name := c.FormValue("name")    return c.String(http.StatusOK, name)}

We use the curl command to simulate a browser sending a form request:

terminal
curl -X POST http://localhost:1324 -d 'name=Joe'// => Joe

Additionally, we can implement the interface Slim#BindUnmarshaler to complete binding of custom data type values:

Custom timestamp type
type Timestamp time.Timefunc (t *Timestamp) UnmarshalParam(src string) error {    ts, err := time.Parse(time.RFC3339, src)    *t = Timestamp(ts)    return err}

Query Parameters

Use the context method Context#QueryParam(name string) to get query parameters by field name:

Get query parameters
// Handlerfunc(c slim.Context) error {    name := c.QueryParam("name")    return c.String(http.StatusOK, name)})

We use the curl command to simulate a browser sending a request:

terminal
curl -X GET http://localhost:1323\?name\=Joe// => Joe

Similar to form data, we can also complete binding of custom data type values.

Path Parameters

Use the context method Context#PathParam(name string) string to get path parameters by the defined parameter name, example:

Get path parameters
s.GET("/users/:name", func(c slim.Context) error {    name := c.PathParam("name")    return c.String(http.StatusOK, name)})

We use the curl command to simulate a browser sending a request:

terminal
curl http://localhost:1323/users/Joe// => Joe

Binding Data

Additionally, we can bind request data to Go structs through Data Binding.

Validating Data

Slim does not have built-in data validation functionality, but we can register a custom validator by setting the Slim instance property Slim#Validator.

The following example uses the https://github.com/go-playground/validator framework for validation:

Using third-party framework
package mainimport (    "net/http"    "log"    "github.com/go-playground/validator"    "go-slim.dev/slim")type (    User struct {        Name  string `json:"name" validate:"required"`        Email string `json:"email" validate:"required,email"`    }    CustomValidator struct {        validator *validator.Validate    })func (cv *CustomValidator) Validate(i interface{}) error {    if err := cv.validator.Struct(i); err != nil {        // Optionally, you could return the error to give each route more control over the status code        return slim.NewHTTPError(http.StatusBadRequest, err.Error())    }    return nil}func main() {    s := slim.New()    s.Validator = &CustomValidator{validator: validator.New()}    s.POST("/users", func(c slim.Context) (err error) {        u := new(User)        if err = c.Bind(u); err != nil {            return slim.NewHTTPError(http.StatusBadRequest, err.Error())        }        if err = c.Validate(u); err != nil {            return err        }        return c.JSON(http.StatusOK, u)    })    log.Fatal(s.Start(":1323"))}

Use the curl command to simulate a browser sending a request

terminal
curl -X POST http://localhost:1324/users \  -H 'Content-Type: application/json' \  -d '{"name":"Joe","email":"joe@invalid-domain"}'{"message":"Key: 'User.Email' Error:Field validation for 'Email' failed on the 'email' tag"}
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